Extra wire from transfer case

[lil_Blue_Ford]

The transfer case is the one that came in the truck back in Jan of 1998 when I bought it with 14 miles on it. Now at 368K, it's been falling apart. LOL
I use to live further out of town on a gravel road that was very steep, so I was always shifting from 2 to 4 high so as to minimize potholes in the gravel. Never had problems then, but that was back in the 2010s. Now I hardly think to put it in 4 wheel drive.
Couldn't tell in the video, do you remember if your connector was 'full' of all 8 wires? Thinking now that I need to look at the new plug on the motor and see if all 8 wires are 'filled in'. If so, I'll try splicing the 'extra wire' in the new motor's plug into the one from the transfer case. Sound logical?

Interesting.

Yes, the 2000 transfer cases that I had which didn’t have the extra wire from the t-case only had 7 wires in the plug and a blank spot. Dad’s 99 had the extra wire and it filled that last spot. Which is why I asked if your truck had 7 or 8 wires on the truck side, if it had 8, then that’s likely where the missing wire goes. If it has 7, then adding a wire to the plug won’t change a thing because there’s nowhere on the truck side to connect. If that makes sense.

But the wire colors on the new motor don't match the original, as far as positions go. And the original plug on mine only had 7 wires installed. So there was one 'blank' in the plug, and the extra wire was the 8th. Was thinking maybe they integrated it into the plug on other years, since your description of the wires don't match my plug. What do you think?

The wire colors changed randomly on the shift motor side. Depended on who made it and when. They can be traced out but should come pre-assembled into the correct position.

 

[lil_Blue_Ford]

Only if it's the same color. Some plugs had more than 8 wires. I would suspect that if it's an 8-wire plug, you will not find anything extra.

2 wires for motor
2 wires for sensor
4 wires for position switches
= 8 wires. There won't be any unused.

On the 99 and the 00 Rangers I’ve worked with there is two heavy gauge wires for the shift motor and 5 for the contact plate. The 99 was the only one with an 8th wire, and that went into the t-case under the rear output. All three were pinned exactly the same other than that 8th wire.

 

[Effieman]

Interesting.

Yes, the 2000 transfer cases that I had which didn’t have the extra wire from the t-case only had 7 wires in the plug and a blank spot. Dad’s 99 had the extra wire and it filled that last spot. Which is why I asked if your truck had 7 or 8 wires on the truck side, if it had 8, then that’s likely where the missing wire goes. If it has 7, then adding a wire to the plug won’t change a thing because there’s nowhere on the truck side to connect. If that makes sense.


The wire colors changed randomly on the shift motor side. Depended on who made it and when. They can be traced out but should come pre-assembled into the correct position.

The extra wire on my case connected to a separate wire that also came out of the motor, so there was a total of 8 wires connected, 7 in the connector, and one with the spade connector. I'm figuring IF the new motor has 8 wires in the connector, then the 8th wire would be for the extra wire that comes from the case, which would seem to be what you explained. Does that make sense?

 

[Curious Hound]

Only if it's the same color. Some plugs had more than 8 wires. I would suspect that if it's an 8-wire plug, you will not find anything extra.

2 wires for motor
2 wires for sensor
4 wires for position switches
= 8 wires. There won't be any unused.

First off, please forgive me. I made some mistakes here. It should read 5 wires for position switches. So, 7 wires installed is normal and expected on the newer trucks with full-time live axles. The speed sensor and clutch are not needed. The older trucks needed 10 wires due to the speed sensor and clutch. There may have been variations over the years. We also know that Ford uses up inventory during model transitions. An early live axle truck could very easily end up with a t-case containing a clutch right from the factory. There is no reason for a third wire from the motor and it especially would not connect to the clutch. The clutch signal would come from the controller in the cab. The motor only needs 2 wires - 1 positive, 1 negative. The controller swaps them to change direction.


The main point is, your truck doesn't seem to need the clutch. So you can ignore that wire. Let it dangle in the wind and move on with life.

 

[Effieman]

First off, please forgive me. I made some mistakes here. It should read 5 wires for position switches. So, 7 wires installed is normal and expected on the newer trucks with full-time live axles. The speed sensor and clutch are not needed. The older trucks needed 10 wires due to the speed sensor and clutch. There may have been variations over the years. We also know that Ford uses up inventory during model transitions. An early live axle truck could very easily end up with a t-case containing a clutch right from the factory. There is no reason for a third wire from the motor and it especially would not connect to the clutch. The clutch signal would come from the controller in the cab. The motor only needs 2 wires - 1 positive, 1 negative. The controller swaps them to change direction.


The main point is, your truck doesn't seem to need the clutch. So you can ignore that wire. Let it dangle in the wind and move on with life.

You mentioned before that the clutch was for slow speeds. Do you know what slow speed would be?
I'm now thinking I should maybe just try to shift on the fly to 4 high at maybe 10 mph and see if I get the grinding noise again. If it sounds good, then I won't worry about the wire.... Since, of course, I have to be stopped with the clutch in and brake on to get into 4 low.

I know the build date on my truck was December of '97. Do you happen to know the cut off year of the live axle?
This seems to be getting complicated. LOL

 

[Curious Hound]

This thread has gotten confusing with people talking about 2000 and newer systems. Let's review and confirm some things. I just looked back and see that we're talking about a '98 and you just confirmed a build date of Dec 97. I believe this actually puts you in the era of the PVH hubs. Not full-time live axles. They are automatic vacuum operated hubs. So, think back to hearing the grinding noise. Are you SURE it came from the transfer case? The PVH hubs are notoriously unreliable and you may have had a hub not fully engaging for one of your front wheels.

One more note. Do not use 4x4 hi or lo on hard surfaces.

To answer your question about shift - on - the- fly speed, see photo below. It mentions being able to do it up to 55mph. I normally stay less than about 35mph, personally.